In the manufacture of automotive vehicles it is necessary to inspect each vehicle for leaks so that any deficiencies can be corrected. Very small opening in door or window seals as well as in sealant-filled joints between panels can admit air or water or simply may be the source of wind noise. The prior practice has been to spray water on a vehicle body and visually locate leakage. This requires that the body be completed with all seals in place but seats and other soft trim which may be damaged by leaking water should not yet be installed. This severely restricts the assembly procedures as well as the inspection process. In addition, many leaks are not detectable with the water test.
It is desirable, therefore, to detect leaks on either closed or open vehicle bodies in any stage of assembly. To meet this objective it has been attempted to use ultrasonic leak detection. Prior to this invention, the ultrasonic procedures were limited to inspection of closed bodies and were ineffective for small leaks, especially those which define a tortuous path, and thus were not acceptable inspection techniques.